Leap Seconds in Red Hat Enterprise Linux

Leap Seconds in Red Hat Enterprise Linux

Systems running NTP

Systems running any version of Red Hat Enterprise Linux should automatically account for leap second corrections if they are using the NTP (Network Time Protocol) daemon to synchronize their local timekeeping with an NTP server. During the last day before a leap second correction, NTP servers should notify their clients that a leap second will occur, and at 23:59:59 UTC, the Linux kernel should add or remove an extra second by making the 60th second twice as long or removing it entirely. Thus, Red Hat Enterprise Linux systems running an NTP client during the last leap second correction should have counted time as follows:

When the leap second occurs, the kernel prints a message to the system log. There is a chance that the printing of this message can cause the kernel to crash in Red Hat Enterprise Linux 4 and 5. To avoid this situation, please update to the latest version of the kernel available: